Adafruit Industries, Essential service and business: NYC – Executive Order 202.6 - Read more.
0

Ice Tube Clock firmware for newbie.
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Re: Ice Tube Clock firmware for newbie.

by jarchie on Tue Feb 10, 2015 11:55 pm

jarchie wrote:
rjhike wrote:Yes I would like the HH._MM._SS.

Okay. I'll look into it.

I just pushed a change to GitHub that allows this kind of time display, but not through a separate format. When configuring the time format, select the usual "HH MM SS" format and then choose one of the new dot-space separator characters.

jarchie wrote:
rjhike wrote:I just ended up putting the chip in the clock and it worked. I didn't have to make any changes that were suggested in the troubleshooting page.

I guess that works too. :-) Since your EEPROM wasn't successfully programmed, it means that the default settings might be a bit bizarre, but you can change those through the clock menus.

Since programming didn't work as expected on the first try, it's possible something similar will happen with you install the new version. For most people--at least those who email me personally about programming trouble--the problem turns out to be that they did not connect the USBtinyISP and clock exactly as described in the firmware/README.

jarchie
 
Posts: 595
Joined: Sun Jun 24, 2012 2:16 pm
Location: Santa Cruz, California, United States

Re: Ice Tube Clock firmware for newbie.

by rjhike on Thu Feb 12, 2015 2:11 pm

I just installed the GPS and the new firmware. Everything is working.
Interesting observation - I have the Ice Tube clock sitting next to another GPS enabled nixie tube clock. The time is off by one second. I thought the would be exactly the same. Oh well.
Easy fix, just put one of the clocks in another room.
Thanks for your instructions and firmware.
What to build next?

rjhike
 
Posts: 15
Joined: Thu Jan 29, 2015 8:35 pm

Re: Ice Tube Clock firmware for newbie.

by jarchie on Thu Feb 12, 2015 4:53 pm

rjhike wrote:I just installed the GPS and the new firmware. Everything is working.

Good. I'm glad you were able to install the firmware update without difficulty.

rjhike wrote:Interesting observation - I have the Ice Tube clock sitting next to another GPS enabled nixie tube clock. The time is off by one second. I thought the would be exactly the same. Oh well.

This is to be expected. The Ice Tube Clock time is only accurate to around one second; your nixie clock might be similar.

Even with the GPS mod, the Ice Tube Clock still keeps its own time with the clock crystal; doing so allows the clock to function when the GPS signal is lost. The microcontroller has an internal counter tied to the clock crystal, and this timer triggers a once-per-second interrupt which is processed by the firmware. The software advances time each second, which means that the time is only kept to seconds resolution in the software. The easiest GPS implementation is to compare the clock time to the GPS time, and update the clock time as needed. This places the GPS synchronization accuracy to about a second.

It is possible to do more exact synchronization by having the firmware manipulate the microcontroller's internal counter. The xmas firmware uses this approach to keep the clock time within a half-second of the GPS reported time. This was a compromise to allow the GPS mod to work well with the automatic drift correction. Although not essential with the GPS mod, the automatic drift correction improves timekeeping accuracy when there is no GPS unit or no GPS signal. Even with a permanently attached GPS, the automatic drift correction helps when the clock loses external power and needs to keep time during sleep.

Most people, including myself, rationalize the one second error as acceptable because time is not transmitted accurately over serial in the first place. Most GPS units, including the Ultimate GPS Module, output a NMEA RMC record which contains the time and position. This record must be formatted by the GPS, transmitted over serial, and parsed by the clock. The process is not instantaneous and requires a tenth or twentieth of a second--most of that due to the transmission time. So to keep exact time, the GPS would need a pulse-per-second output pin, and the clock would need to process that information.

rjhike wrote:Thanks for your instructions and firmware.

You're welcome!

jarchie
 
Posts: 595
Joined: Sun Jun 24, 2012 2:16 pm
Location: Santa Cruz, California, United States

Re: Ice Tube Clock firmware for newbie.

by rjhike on Sat Feb 21, 2015 1:31 pm

How can I send a personal message / email to you (jarchie) about another project?

rjhike
 
Posts: 15
Joined: Thu Jan 29, 2015 8:35 pm

Re: Ice Tube Clock firmware for newbie.

by jarchie on Sat Feb 21, 2015 3:08 pm

Here's my email.

jarchie
 
Posts: 595
Joined: Sun Jun 24, 2012 2:16 pm
Location: Santa Cruz, California, United States

Please be positive and constructive with your questions and comments.